Alma 50:1 - 50:5
Alma 50: 1 And now it came to pass that Moroni did not stop making preparations for war, or to defend his people against the Lamanites; for he caused that his armies should commence in the commencement of the twentieth year of the reign of the judges, that they should commence in digging up heaps of earth round about all the cities, throughout all the land which was possessed by the Nephites.
While peace seemed to be the situation at the moment, Moroni knew that the defenses built so far, which were only around the areas near the wilderness side, would not be enough. Amalickiah would be back with more fighters and more determination to bring the Nephites under his domination. Knowing this Moroni had his armies fortifying all of the cities of the Nephites like was done to Ammonihah and Noah.
Great lesson here. Even though things might seem to be going our way, we need to be prepared for the enemy of our souls by doing even more to defended ourselves for the onslaught of satan. He will return to attach us again. Well need to be thinking of different ways he might hit us and create defenses for them. One thing is for sure, he will not give up trying to bring us under his domination just like Amalickiah.
Alma 50: 2 And upon the top of these ridges of earth he caused that there should be timbers, yea, works of timbers built up to the height of a man, round about the cities.
Not only did he have earthen mounds installed around the cities with deep ditches in front of them, but he also installed six foot or so high wooden fence on top of the mounds.
Alma 50: 3 And he caused that upon those works of timbers there should be a frame of pickets built upon the timbers round about; and they were strong and high.
On top of the wooden wall were pointed spikes to keep men front trying to scale the walls.
Alma 50: 4 And he caused towers to be erected that overlooked those works of pickets, and he caused places of security to be built upon those towers, that the stones and the arrows of the Lamanites could not hurt them.
Every so often, towers were built to overlook the walls from which were shielded from the arrows and stones of the enemy.
Alma 50: 5 And they were prepared that they could cast stones from the top thereof, according to their pleasure and their strength, and slay him who should attempt to approach near the walls of the city.
From these towers the Nephites could shoot arrows and throw stones at the enemy.